Critical appraisal of an article on a diagnostic test

1
Critical appraisal of an article on a diagnostic
test
2
The clinical question

• P In children with fever and petechiae,
• I does looking ill
• C compared to looking well (not looking ill)
• O increase the risk of bacteremia?

3
The search strategy

• Keywords petechiae AND sensitivity
• In PubMed Clinical Queries section
• limited to diagnosis
• broad, sensitive search

4
The search result

• Mandl KD, Stack AM, Fleisher GR. Incidence of
  bacteremia in infants and children with fever and
  petechiae. J Pediatr 1997131398-404.

5
Is it valid?

• Independent, blind comparison with gold standard?
• Yes (blood culture)
• Appropriate spectrum of patients?
• Yes (all patients in emergency
• department with fever and petechiae)
• Gold standard applied to ALL patients?
• Yes

6
Are the results important?
7
Looking ill and Bacteremia
Mandl KD, Stack AM, Fleisher GR. Incidence of
bacteremia in infants and children with fever and
petechiae. J Pediatr 1997131398-404.
8
Looking ill and Bacteremia
Mandl KD, Stack AM, Fleisher GR. Incidence of
bacteremia in infants and children with fever and
petechiae. J Pediatr 1997131398-404.
9
Is it applicable?

• Is the test available and affordable?
• Yes
• Is the test accurate and precise in your setting?
• Yes if we follow criteria
• given in the article
• Will the post-test probabilities affect our
  management?

10
Will the post-test probabilities affect our
management?
LR()6.41

• The patients probability of having bacteremia
  has increased from 2 to 13.
• Do you consider this significant enough to
• Perform further tests?
• Treat the patient on the basis of test results?

posttest prob
pretest prob
2
13
0 .10 .20 .30 .40 .? 1
Pretest odds x LR()